The semiconductor industry has experienced exponential growth, and has progressed in pursuit of higher device density and performance, and lower costs. However, the classical planar transistor cannot achieve such goals due to physical constraints. Accordingly, various non-planar transistors, such as a fin-like field-effect transistor (FinFET), have been developed.
The FinFET includes a source, a drain, one or more semiconductor fin structures between the source and the drain, and a gate stack across the semiconductor fin structures. The manufacturing of the FinFET is focusing on the scaling down of dimensions of the FET to improve the packing density of the semiconductor device. With the high demands on scaling down of the FET, the method for manufacturing such FinFET has to be continuously improved so as to obtain a more satisfactory FinFET structure.